Remove implicit conversions

Implicit conversions are something that nlohmann library itself is a bad
default, and 3 years ago threatened to change the default.  These
implicit conversions cause a number of crashes that are hard to
reproduce, because they throw an uncaught exception.

Update the code to be able to do no more implicit conversions.

Tested: Entity-manager launches and runs.  Items are detected correctly
and show up on dbus.  Unit tests pass.

Change-Id: Ib23159ae58f5584641427d9be7545bc25a3619af
Signed-off-by: Ed Tanous <etanous@nvidia.com>
diff --git a/src/entity_manager/entity_manager.hpp b/src/entity_manager/entity_manager.hpp
index 70f7a4f..aa1c7ea 100644
--- a/src/entity_manager/entity_manager.hpp
+++ b/src/entity_manager/entity_manager.hpp
@@ -53,7 +53,7 @@
                                  nlohmann::json newConfiguration);
     void postToDbus(const nlohmann::json& newConfiguration);
     void postBoardToDBus(const std::string& boardId,
-                         const nlohmann::json& boardConfig,
+                         const nlohmann::json::object_t& boardConfig,
                          std::map<std::string, std::string>& newBoards);
     void postExposesRecordsToDBus(
         nlohmann::json& item, size_t& exposesIndex,